So-called fuel injection installations are used in modern engines to supply internal combustion engines with fuel. They are used regardless of whether the engine is a so-called gasoline engine or a diesel engine. Constructions in which a so-called nozzle assembly is inserted directly into the cylinder head are used to inject the fuel into the combustion chamber. The nozzle assembly passes through a so-called calve cover mounted on the cylinder head and is pressed, for example, into a mounting hole of the cylinder head. The nozzle assembly has an approximately cylindrically shaped mounting section for this purpose. At its end directed toward the combustion chamber, this nozzle assembly is provided with the injection nozzle proper. At its opposite end protruding from the cylinder head, the nozzle assembly has a radially expanded head part, which is provided with a connection pipe for the fuel supply, on the one hand, and with a connector plug for actuating a control valve arranged in an integrated manner in the head part, on the other hand.
To secure the nozzle assembly in the mounting hole of the cylinder head, the mounting shaft of the nozzle assembly has, directly below its head part, two lateral milled-out recesses, which form a stop face towards the head part, on the one hand, and another pair of stop faces toward the injection nozzle, on the other hand. These milled-out recesses form two sides extending in parallel to one another and in parallel to the central longitudinal axis of the nozzle assembly. To secure the nozzle assembly in the hole of the cylinder head, a fork-shaped clamping claw each is provided, which engages with its fork legs the milled-out recesses of the mounting shaft and holds the nozzle assembly tightly in the hole of the cylinder head via the stop faces of the milled-out recesses, which said stop faces are directed toward the injection nozzle. The clamping claw is fastened to the cylinder head by means of a mounting screw.
Furthermore, in the area of its end area located opposite the two fork legs, the clamping claw has a support lever, which is provided with a depression. With this depression of the support lever, the clamping claw is supported on a pressing ball, which is arranged in the valve cover of the cylinder head and partially projects from the valve cover of the cylinder head vertically in the upwardly direction. Together with the support lever of the clamping claw, this pressing ball forms a type of pivoted mount of the clamping claw, so that the latter secures the nozzle assembly in the hole of the cylinder head with its fork legs when the mounting screw is tightened. Furthermore, the nozzle assembly can also be pressed into the mounting hole of the cylinder head with the clamping claw because of this special mounting of the nozzle assembly via the stop faces of the milled-out recesses. Furthermore, the nozzle assembly is also fixed in its angular position by the fork legs of the clamping claw.
It was now found that it is extremely difficult to extract such a nozzle assembly from the mounting hole of the cylinder head after a longer operating time of the internal combustion engine.
Moreover, it should be noted that the valve cover extends upwardly up to the head part of the nozzle assembly in the area surrounding the head part of the nozzle assembly and it has only a short distance from the head part. There is only an extremely short distance between the valve cover and the head part of the nozzle assembly especially in the areas extending at right angles to the clamping claw.
Furthermore, the electric connector plug is screwed onto the head part and can be removed to remove the nozzle assembly from the head part. An internal thread arranged in the head part is freely accessible for attaching an extraction device after the removal of this connector plug, i.e., a type of support pipe, which is supported at the valve cover in the area surrounding the one through hole of the valve cover during the subsequent extraction operation, can be actually pushed over the head part to extract the nozzle assembly. However, because of the extremely short distance between the valve cover and the head part of the nozzle assembly, such a support pipe can be provided with an extremely small wall cross section only to be pushed into the intermediate space between the head part and the valve cover. This has, in turn, the consequence that especially in case of extremely strong tensile forces, deformation will occur due to the high surface pressure between the front surface of the support pipe and the surface of the valve cover. This high surface pressure leads to unacceptable deformations in the area surrounding the through hole of the valve cover, so that the latter may possibly have to be replaced after the extraction of the nozzle assembly.